Copper cooled valve



Feb 7, 1933. F. c. CRAWFORD v COPPER COOLED VALVE Filed Feb. 13

` federmccraw/fofd Patented Feb. 7, 1933 yUNITED s'rxrizs PATENT OFFICE FREDERICK CCItAWFORD, 0F CLEVELAND,'OHIO, ASSIG1NOR TO THOMPSON PRODUCTS,

` INCORPORATED, F CLEVELAND, OHIO, A CORPORATION 0F OHIO corran cooLED VALVE Appimation nica rebruary'is, 1931. yseimila. 515,567.

' The temperatures attained in the combustion chambers of automotive engines closely approximate thetemperatures to which the metals used in the manufacture of valves are :2'5" The other method of cooling the valve, as

heated in suchv manufacture. The gases which pass the exhaust valves maintain the exhaustpassageway at a temperature of around 1600O F. for ordinary engine speed. These gases have a very destructive effect on the valves causing corrosion and warping and producing a destructive change in the metall of the valve. Since these gases arel directed against a portion of the valve which includes the upper ortion of its stem and the lower portion o the head, it has been a ,problem for valve manufacturers to devise a means of cooling this kportion ofthe valve.-

This cooling has been accomplished in several ways such as providing a shield about this portion and also by filling the stem of the valve with a cooling medium which will draw the heat to a portion of the valve which may be cooled by outside means.- The first of these methods is objectionable because its eiii'ect depends upon the formation of a dead air space between the protecting shield and the valve. In this type of valve the heat being directed against the protecting shield will have a destructive action yon the shield and will in time eliminate the dead air space.

heretofore practiced, while more permanent in nature, has been found not entirely satisfactory for the reason that it involves a considerable expense and careful` planning or else the cooling medium is not very effective. VAAccording to the present invention, a

simple and inexpensive means'for cooling the medium therein.. Y

It is a further object of this invention to produce a metallic cooled valve by a method which is inexpensive, expedient and adapted for use in large scale production of valves.

It isa particular object of this invention to produce a valve of this type by a method which includes the welding Yof va cooling medium within the stem of the valve in such a vmanner as to produce a joint therebetween which has avery high rate of heat conduce v tivity.

`These and other objects of this invention will appear from the followingdescription and appended claims.

. i This invention .(in a preferred form) is illustrated f and described in this specification and accompanying drawing-.which forms a part thereof. f l `O n the drawing:

- Figure l is a sectional view of a partially linishedvalve,v showing acopper rod inserted inv a bore formed inthe stem.

. Figure 2 is a sectional view of anl unfinished valve showing the copper rod Welded therein. f f

Figure Sis a sectional view of an un-y finished valve showing a bore formed therein by drilling arecess in the copper.4

. Figure 4 is a sectional view of an imfinished valve showing a .result of4 a further step in formingthe valve.

Figure 5 is a sectional view of a completed valve. n, As shown on the drawing:

Incarrying out this invention, a member 1 lof, the general'sliape of a valve is formed in thel usual manner of valve. making as by forgingablank or upsetting va rod.v The metalblank in this stage of they operation is formed kwith astem 2 and a head 3. A portion Ll-.of enlarged diameter is left at the end of thek stein. f ,A "A boreor recess is drilled through the end ofthe stem and lextends throughout the length of the stem. The bore 5is preferably `cylindrical in shape. A copper rod'6 which vis of suiiciently large diameter tosnugly iillV the bore ands'of greater length, is inserted into' thev recess 5. The rod 6 may be of any metal having a veryhigh rate of conductivity,.but copper or a copper alloy is the most satisfactory. r: .Y

, ion

The valve 1 is then placed on its head end into a furnace in which an atmosphere of hydrogen or other non-oxidizing, and pref-r Y bra-zes itself to the steel and forms a perfect joint 8. The flux 7 Hows down along the copper and the joint which is formed throughout the extent of the contacting steel and copper surfaces, has no oxidized portions or air pockets. The result is a bond between the copper and the steel which has a rate of heat conductivity of approximately 97% of that of the steel alone, whereas ordinarily even a welded joint will offer a very material resistance to the iiow of heat.

After this operation the valve is removed from the furnace and the center of the copper is drilled out leaving a copper shell 9 permanently brazed or welded to the steel. The term welded is used here and in the claims to include any method wherein heat is used to effect a bond between the metal of the insert and of the wall of the stem.

The valve is again reheated and the thickened portion 4 of the stem worked down, as by swaging, to the diameter of the remaining portion of the stem. In this operation the metal of the enlarged portion 4 is used to close the bore of the stem as shown at 10. The end of the copper shell 9 is drawn out as shown at 11 so as to form a solid closure for the stem.

The valve head is then worked into the finished shape as shown at 12 and the stem end may be suitably threaded as shown at 13. A wearing surface 14, comprising a disc of metal, is preferably spot welded to the stem of the finished valve.

he valve produced by this method 'is very effective in conducting the heat from the portion of thevalve in contact with the hot exhaust gases to other portions of the valve which may be cooled by external means. The conductivity of `the copper shell is approximately ten times that of the metals ordinarily used in the making of valves. The joint between the copper and the outer metal of the valve has a rate of heat conductivity of about 97% of the rate of heat conductivity ofthe outer metal. A loose joint between copper and steel has a conductivity of about 40%.

It will thus be seen that this invention provides a self contained metal cooled valve which is economical in its manufacture and efficient in use.

Many changes may be made in the design and proportion of parts, and I do not wish to be limited otherwise than is necessary by the prior art and the scope of the appended claims.

I claim as my invention:

1. As a new article of manufacture, a

hollow stem valve having a metal shell withif; said hollo7 stem welded to the walls thereo 2. As a new article of manufacture, a valve having a hollow stem and a metal shell within said steln welded to the wall thereof with a non-oxidized bond between the shell and the Wall of the valve stem.

3. A valve having a recess in the stem thereof, a copper shell within and completely filling said recess, said shell being welded to the wall of said recess at all points to provide a non-oxidized bond therebetween.

In testimony whereof I have hereunto subscribed my name at Cleveland, Cuyahoga County, Ohio.

FREDERICK C. CRAWFORD. 

